GF1 + 20mm pancake under fluorescent light banding

Is it in the recorded images/video or just in the live-view while you're taking the pictures?

 

Maybe this

I recall that in previous life as a mechanical maintenance person it was unsafe to use a fluorescent light above a rotating machine, such as a grinder or lathe. It is to do with the frequency of the light source sometimes matching that of the RPM of the rotating machine, giving the illusion that it was stationary. A dangerous situation. I expect that the banding you see is this frequency and although visible on the LCD will not appear on the image.
Lynn

 

I've had the same kind of banding and if it's the same reason, it is caused by the frequency of the light source and the refresh rate of the live view. The reason why it didn't show up with the kit zoom lens might be the smaller maximum aperture and that way the sensor wasn't in bad sync with that particular light source. Correct me if I am totally lost here.  

So I believe your "problem" is totally normal and you should not be worried about that.

 

Lumix GF-1 Horizontal Banding

Actually, horizontal banding occurs quite often for me on my Lumix GF-1. It exhibits itself especially bad under fluorescent lighting and when room lighting mixes with outside sunlight. I have posted photos and a video here (be sure to read the description under the photos and video for more info):

[ame=https://www.youtube.com/watch?v=CiZnA1RnrkM]YouTube - Lumix GF1 horizontal stripes induced by fluorescent lighting & high contrast scenes[/ame]
Lumix GF1 Color Banding Problem with Fluorescent Lighting | Flickr - Photo Sharing!

Changing the shutter to 1/60s is a cure, but we cannot do this in every situation, nor can my wife, who prefers to use the Full Auto mode on our GF-1.

I cannot help but view this as a "camera defect," regardless of whether it may affect other cameras as well. Since it is so common, camera makers should do something to prevent it from happening. I feel strongly about this, since none of the cameras I've used in the past (all my Canon PowerShot series, and my miniDV Panasonic PV-GS400 video camera) have every had this kind of banding problem.